JPH0325778B2 - - Google Patents

Description

[Detailed description of the invention]

1. Industrial Application Field The present invention relates to a photoreceptor, particularly an electrophotographic photoreceptor. 2. Prior Art In general, with the exception of a few substances such as amorphous selenium, it is difficult to form a film on the surface of substances that absorb visible light and generate carriers. It has the disadvantage of poor retention of a given charge. On the contrary, materials that have excellent film-forming ability and can retain a charge of 500 V or more for a long time with a thickness of about 10 μm generally have the disadvantage of not having sufficient photoconductivity due to absorption of visible light. have. For this reason, as shown in FIG. 1, a carrier generation layer 2 containing a substance that absorbs visible light and generates charge carriers is provided on the substrate 1, and whether the charge carriers generated in this carrier generation layer are positive or negative is It has been proposed to provide a laminate 4 with a carrier transport layer 3 that transports one or both of them, and to configure the photosensitive layer with this laminate. In this way, by assigning the generation and transport of charge carriers to separate substances, the range of material selection is widened.
It has become possible to enhance or improve various properties required in the electrophotographic process, such as charge retention, surface strength, sensitivity to visible light, and stability during repeated use. However, an excellent electrophotographic photoreceptor that is easy to manufacture, has sufficient electrophotographic properties, and is stable against environmental changes has not been known to date. For example, when the carrier generation layer is composed of amorphous selenium, it is manufactured using a vacuum evaporation apparatus while controlling the degree of vacuum and the temperature of the evaporation source. It is extremely difficult to obtain a stable deposited film. Moreover, since amorphous selenium is thermally unstable, crystallization progresses at temperatures of 50° C. or higher, and it no longer functions as a carrier generation layer. Therefore, especially in an electrophotographic photoreceptor in which a carrier generation layer made of amorphous selenium is provided on a conductive support and a carrier transport layer is coated thereon, the drying temperature of the carrier transport layer after coating is set at 50°C. ℃ or below, making economical production nearly impossible, and the produced electrophotographic photoreceptors had problems with their shelf life. In addition, when the carrier generation layer is composed of a perylene pigment, if a vacuum deposition method is used, it is difficult to obtain a uniform deposited film in the width direction and length direction, as in the case of amorphous selenium. The deposited film thus obtained has a disadvantage in that it is difficult to handle when applying a carrier transport layer because of its poor scratchability.
Although there is a description in U.S. Patent No. 3,904,407 that a perylene pigment is dispersed in a binder resin to form a carrier generation layer, it has not been put to practical use because the electrophotographic properties such as sensitivity are significantly inferior to vapor deposition methods. It has not been. 2. Description of the Related Art An electrophotographic photoreceptor is known that uses an organic pigment as a carrier generating substance in the carrier generating layer and has a carrier generating layer made of a vapor-deposited film of the organic pigment. Since this carrier generation layer is a densely deposited organic pigment free of impurities, it is preferable in that relatively high photosensitivity can be obtained even if it is a thin layer. However, its production requires a large continuous vapor deposition device, and it is extremely difficult to control the film thickness, and it is difficult to form a carrier generation layer with a uniform thickness over the entire surface of the conductive support. is difficult and therefore very costly.
Furthermore, the vapor-deposited organic pigment film has low adhesion to the support and has extremely low strength, so it is prone to scratches and other defects. subject to many restrictions. Moreover, in many cases it is effective to add appropriate additives to improve the properties of the organic pigment, but with the vapor deposition method, there are limits to the type and amount of substances that can be mixed in, and it is difficult to mix them uniformly. It is difficult and almost impossible to improve the characteristics. Due to the above-mentioned circumstances, to date, no electrophotographic photoreceptor has been provided that uses organic pigments and has actually good characteristics. In view of the above-mentioned circumstances, the present applicant has developed a technology that is capable of consistently forming clear copy images with high sensitivity to visible light, and that is uniform over a long length, inexpensive, and that cannot be obtained using vacuum evaporation methods. An electrophotographic photoreceptor having a carrier generation layer that can be stably produced and has excellent scratch resistance has already been proposed in Japanese Patent Application No. 34539/1983. In this prior invention, the above-mentioned excellent effects are exhibited by dispersing a polycyclic quinone pigment such as anthoanthrone in the form of photoconductive particles in polycarbonate. On the other hand, the present applicant has used a purified pigment obtained by sublimation-purifying an organic pigment with sublimation property as an electrophotographic photoreceptor that has extremely excellent properties not only in electrophotographic properties but also in manufacturing and use. An electrophotographic photoreceptor in which a photosensitive layer is constituted by a pigment-containing layer obtained by applying a liquid containing the same has already been proposed in Japanese Patent Application No. 143,699/1983. The present inventor conducted studies to improve these prior inventions, and as a result, discovered the following problems. That is, if the above-mentioned commercially available polycyclic quinone pigment is used as a carrier generating substance as it is, the crystal shape of the pigment is not well-organized and a large amount of additives act as impurities, resulting in insufficient sensitivity. In addition, when a large number of copies are repeatedly made, the potential of the background portion of the image (blank paper potential) may rise and fog may occur. In addition, the above-mentioned sublimation purification makes it possible to grow crystals with high purity, resulting in higher sensitivity than when conventional pigments are used as is. Therefore, simply dispersing it in an organic solvent will only yield particles with a large particle size. Moreover, since pigments such as the above-mentioned anthoanthrone generally do not dissolve in solvents, when such a pigment dispersion is applied to form a carrier generation layer, the particle size of the photoconductive particles (pigment particles) may be affected. I found out that I can put it away.
In other words, the dispersibility of the pigment particles is not very good and the stability of the coating solution tends to deteriorate, and as shown in an enlarged view in FIG. Following this, convex portions 6 are also formed on the surface of the carrier transport layer 3, which deteriorates the smoothness of the surface of the photoreceptor. As a result, when the entire surface of the photoreceptor is charged during use, discharge 7 occurs at the position of the convex portion 6, and local discharge breakdown is likely to occur. In addition, toner particles 8 adhere to the convex portions 6 and remain as they are, causing a so-called toner filming phenomenon, which causes black spots and the like on images. In the phenomenon shown in Fig. 2, the carrier generation layer 2 is formed to be very thin, several micrometers or less, to ensure sufficient electron mobility, and is packed with pigment particles closest to each other to improve sensitivity. It will be understood that the influence of the particle size of the pigment particles 5 and its variation is likely to occur on the surface of the photoreceptor, and the above-mentioned convex portions 6 are likely to be formed. Additionally, the present inventors have discovered that in conventional photoreceptors, sufficient studies have not been made on the combination of carrier-generating substances and carrier-transporting substances. I found out that it wasn't. 3. Purpose of the Invention The purpose of the present invention is to provide a product that has high sensitivity and color sensitivity, excellent operational stability during repeated use, can be manufactured uniformly and stably, has excellent surface smoothness, and is free from local discharge damage. It is an object of the present invention to provide a photoreceptor having good durability and free from toner filming. Another object of the present invention is to provide a coating-type photoreceptor that improves the dispersibility and dispersion stability of a coating liquid, and that is easy to manufacture and can be obtained at low cost. Still another object of the present invention is to provide a photoreceptor with high sensitivity, excellent color sensitivity, and good operational stability during repeated use by specifying a combination of a carrier-generating substance and a carrier-transporting substance. It's about doing. 4 Structure of the invention and its effects That is, the present invention comprises at least one kind selected from the group consisting of each polycyclic quinone pigment of the following general formula (A), (B) or (C), and which is purified by a sublimation purification method. 1. A photoreceptor characterized in that photoconductive particles having an average particle diameter of 2 μm or less obtained by the method are used as a carrier generating substance, and a hydrazone derivative of the following general formula P is used as a carrier transporting substance. (However, in each of the above formulas, X represents a halogen atom, a nitro group, a cyano group, an acyl group, or a carboxyl group, n represents an integer of 0 to 4, and m represents an integer of 0 to 6.) (However, in the above formula, R ¹ represents a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, and R ² represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. In the expression, X' is a hydrogen atom, a halogen atom, an alkyl group,
It represents a substituted amino group or alkoxy group, and l represents an integer of 0 or 1. ) According to the present invention, since the above polycyclic quinone pigment is used as the photoconductive particles, the sensitivity is higher than that of conventional inorganic particles or perylene pigments, and the photosensitive material is uniform and has good scratchability. You can get layers. In addition, since a polycyclic quinone pigment prepared by sublimation purification is used, it has higher sensitivity than photoreceptors using unpurified organic pigments, and can be repeatedly copied many times. Even in this case, since the accumulated residual potential is small and the potential increase in the background portion of the image is small, a clear copy image without fogging can be obtained. However, since the pigment purified by sublimation has a large particle size, the above-mentioned problems tend to occur. A notable feature of the present invention is that a polycyclic quinone pigment obtained by sublimation purification is contained in the photosensitive layer with an average particle size of 2 μm or less. That is, the present inventor determined that the average particle size of the above pigment (since the polycyclic quinone pigment is a needle-like crystal, the length of its long axis is used as the average particle size).
Only by miniaturizing it to 2 μm or less,
The effect of the particle size on the photoreceptor surface can be prevented,
They discovered that the surface of the photoreceptor could be made smooth. If the average particle size of the polycyclic quinone pigment exceeds 2 μm, convex portions 6 as shown in Figure 2 will occur on the surface, but if the average particle size is 2 μm or less, such convex portions can be virtually eliminated and a flat surface can be achieved. It is. As a result, it is possible to obtain a photoreceptor that does not suffer from discharge breakdown or toner filming. It is essential that the average particle diameter of the polycyclic quinone pigment is 2 μm or less, preferably 1 μm or less, and more preferably 0.5 μm or less. However, if the average grain size is too small, crystal defects will increase and sensitivity and repeatability will decrease, and there will be a limit to miniaturization.
It is desirable that the lower limit of the average particle size is 0.01 μm. In order to obtain a polycyclic quinone pigment having such an average particle size, it is desirable to grow the crystals by a sublimation purification method and then actively and thoroughly crush the particles using a crushing device. Examples of the crushing device include a ball mill, a hammer mill, a sand grinder, a centrifugal mill, a colloid mill, a jet mill, and a turbo mill. Further, according to the present invention, since the hydrazone derivative of the general formula (P) is used as a carrier generating substance in combination with the polycyclic quinone-based photoconductive particles, the carrier transport ability is improved and it can be used repeatedly. The operation in is stabilized. The liquid used to form the photosensitive layer in the present invention has an average particle size of the above polycyclic quinone pigment.
It can be obtained by dispersing photoconductive particles of 2 μm or less in a suitable organic solvent (which preferably contains a binder resin to improve adhesiveness). Further, before and/or after this dispersion step, a carrier transport substance can be added depending on the purpose, thereby improving the charge transport function of the photocarrier generation layer itself.
In addition, as a dispersion method, for example, a method using a ball mill, a homogenizer, a sand grinder, a colloid mill, an ultrasonic wave, etc. can be applied. Specific examples of the anthrone pigment represented by the above general formula (A) used in the present invention are as follows. Specific examples of the dibenzpyrenequinone pigment represented by the general formula [B] are as follows. Specific examples of compounds of the pyranthrone pigment represented by the general formula [C] are as follows. Furthermore, the following are specific examples of the hydrazone derivative represented by the general formula (P). Further, examples of the binder resin that can be used in the present invention include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin,
Addition polymerization type resins, polyaddition type resins, polycondensation type resins such as vinyl acetate resin, epoxy resin, polyurethane resin, phenolic resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and repeating units of these resins Examples of copolymer resins containing two or more of these include vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, and the like. However, the binder resin is not limited to these, and all resins commonly used in such applications can be used. In particular, polycarbonate resins include linear polymers having repeating units represented by the following general formula []. General formula [] In the formula, R' ₁ and R' ₂ are each a hydrogen atom, an alkyl group such as methyl, ethyl, propyl, isofuropyl, butyl, t-butyl, pentyl, hexyl,
Heptyl, octyl, nonyl, decyl, etc., or an aryl group such as phenyl, naphthyl, etc., and R' ₁ and R' ₂ jointly represent a hydrocarbon ring (cycloalkane ring such as cyclohexyl ring, polycyclo (including an alkane ring). Further, R' ₃ , R' ₄ , R' ₅ and R' ₆ each represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom such as a chlorine atom, a bromine atom, an iodine atom, and A is

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】 and

[Formula] Represents a divalent group selected from the following. The alkyl group in R' ₁ and R' ₂ preferably has 1 to 22 carbon atoms, and the hydrocarbon ring preferably has 5 to 7 members, and the carbon atoms of the hydrocarbon ring are preferably 5 to 7 members. The total number is preferably in the range of 5 to 19. In addition, polycarbonate resins particularly preferably used in the present invention include linear polymers containing repeating units represented by the following general formula []. General formula [] Here, R' represents a phenylene group, a halogen-substituted phenyl group, or an alkyl-substituted phenylene group (particularly an alkyl-substituted phenylene group having 1 to 20 carbon atoms), and R' ₁ and R' ₂ each represent the general formula of the polycarbonate [] The same as R′ ₁ and R′ ₂ in . In the general formulas [] and [], each group and each ring are not limited to unsubstituted ones, and include, for example, halogen atoms (e.g., chlorine atom, bromine atom, iodine atom, etc.), alkyl groups (e.g., carbon atoms of 1 to 20), It also includes those having substituents such as alkyl groups) and aryl groups. Further, examples of the organic solvent used in the present invention include methylene chloride, methylene bromide,
1,2-dichloroethane, Sym-tetrachloroethane, Cis-1,2-dichloroethylene, 1,
Examples include single solvents such as 1,2-ylichloroethane, chloroform, bromoform, dioxane, tetrahydrofuran, and pyridine, or various mixed solvents containing these as main components. 5 Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Figure 3 shows the average particle size in the carrier generation layer 2.
This figure shows a functionally separated type electrophotographic photoreceptor containing the above-mentioned polycyclic quinone pigment particles 5 of 2 μm or less. In this case, the carrier generation layer 2 may or may not contain a binder resin. Even if they are not contained, the polycyclic quinone particles 5 can be retained in the photosensitive layer because the carrier transport layer 3 is provided as an upper layer. The dry film thickness of the carrier generation layer 2 is 0.05 to 10 μm, preferably 0.1 to 5 μm, and can be applied by ordinary dip coating,
It is applied by a coating method such as knife coating, roll coating or spray coating. In carrier generation layer 2,
The binder is preferably used in an amount of 0 to 500 (preferably 0 to 200) parts by weight per 100 parts by weight of the carrier generating substance (polycyclic quinone). Outside this range, if the binder exceeds 500 parts by weight, sensitivity will be insufficient. The carrier transport material used in the carrier transport layer 3 is the above-mentioned hydrazone derivative. The blending ratio of the binder resin and the carrier transport material is 10 to 300 parts by weight (preferably 50 to 200 parts by weight) of the carrier transport material per 100 parts by weight of the binder resin.
It is good to be. Outside this range, if the amount of the carrier transport substance is too small, the effect will be poor, and if it is too large, the film forming ability will be poor and the charge retention property will be reduced. Further, the thickness of this carrier transport layer 3 is 2 to 100 microns, preferably 5 to 30 microns. The carrier transport layer 3 may contain various additives for the purpose of improving flexibility, reducing residual potential, and reducing fatigue during repeated use.
Such additives include diphenyl, diphenyl chloride, o-terphenyl, p-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphate,
Examples include methylnaphthalene, benzophenone, chlorinated paraffin, dilaurylthiopropionate, and the like. In FIG. 4, the photosensitive layer 4 is replaced with the above-mentioned polycyclic quinone particles 5.
2 dispersed in the above carrier transport substance 3
An example is shown in which a substance consisting of phases is formed. In this case, it will still be a functionally separated type, but it can perform both the carrier generation and transport functions at the same time. In this case, in the photosensitive layer 4, the carrier generating substance 5 is preferably used in an amount of 1 to 200 (preferably 10 to 100) parts by weight per 100 parts by weight of the binder; however, if it is less than 1 part by weight, the sensitivity is poor. This is because if the amount exceeds 200 parts by weight, the film forming ability will deteriorate. In addition, the carrier transport material is per 100 parts by weight of binder.
It is preferable to use 10 to 300 parts by weight (preferably 50 to 200 parts by weight), because if it is less than 10 parts by weight, the effect will be poor, and if it exceeds 300 parts by weight, the film forming ability and charge retention ability will decrease. be. The polycyclic quinone pigments mentioned above are different from ordinary dye-type pigments and are difficult to dissolve in solvents, but they have good weather resistance and have a specific crystal structure, so they have extremely excellent semiconductor properties. It has become a thing. In addition, in the carrier transport layer or photosensitive layer, a Lewis acid of 0.001 to 10% (preferably
It may be added in an amount of 0.01 to 1)% by weight. Lewis acids that can be used include succinic anhydride, maleic anhydride, dibromaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, Pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, 1,3,5-trinitrobenzene, paranitrobenzonitrile, picryl chloride, quinone chloroimide, Chloranil, bromanil, dichlorodicyanoparabenzoquinone, anthraquinone, dinitroanthraquinone, 2,7-dinitrofluorenone, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, 9-fluorenylidene-[dicyanomethylene malonodinitrile], polynitro-9-fluorenylidene-[dicyanomethylene malonodinitrile], picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrobenzoic acid salicylic acid,
Examples include 3,5-dinitrosalicylic acid, phthalic acid, mellitic acid, and other compounds with high electron affinity. Moreover, as the above-mentioned base 1, a conductive support is suitable, but a conductive film such as Al may be provided on the surface of the insulating support and a photosensitive layer may be formed thereon. As the material of the conductive support 1, for example, metals such as aluminum, nickel, copper, zinc, palladium, silver, indium, tin, platinum, gold, stainless steel, and brass can be used. Further, each of the photosensitive layers described above can also be formed on an intermediate layer (not shown) provided on a conductive support. This intermediate layer prevents the injection of free carriers from the conductive support into the photosensitive layer when the photosensitive layer is charged, and also functions as an adhesive layer that holds the photosensitive layer integrally bonded to the conductive support. fulfill Materials for this intermediate layer include metal oxides such as aluminum oxide and indium oxide, addition polymerization resins such as acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, and epoxy resin;
Polyaddition type resins, polycondensation type resins, and copolymer resins containing two or more of the repeating units of these resins, such as vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-maleic anhydride Examples include acid copolymer resins. However, the resins that can be used here are not limited to these, and all resins that are commonly used for this purpose can be used. Next, specific examples of the present invention will be described. Example 1 Commercially available anthinthrone pigment “Monolite Red 2Y” represented by structural formula A3 (manufactured by ICI, CI No.
59300) was filled into a graphite evaporation source placed in a vacuum evaporation apparatus, sublimated at a temperature of 370°C for 60 minutes, and deposited on a substrate placed 25 cm above the evaporation source. After pulverizing 30 g of the obtained purified pigment in a ball mill for 24 hours, 1000 ml of 1,2-dichloroethane was added and a dispersion treatment was carried out for 24 hours to obtain a coating solution for forming a carrier generation layer. Next, the dry weight is 0.1 on a 120φ aluminum drum.
g/m ² of vinyl chloride-vinyl acetate-maleic anhydride copolymer resin "Eslec MF-10" (manufactured by Sekisui Chemical Co., Ltd.) by a dip coating method, and then the carrier generation described above was applied. A layer-forming coating solution was applied onto the intermediate layer by the same dip coating method to obtain a carrier generation layer having a dry weight of 2.3 g/m ² . As a result of observation with an electron microscope,
The carrier generation layer was filled with pigment particles having an average particle size of 0.3 μm. On the other hand, hydrazone derivatives represented by structural formula P32
112.5g and 150g of polycarbonate resin "Panlite L-1250" (manufactured by Teijin Chemicals),
The coating solution for forming a carrier transport layer obtained by dissolving in 1000 ml of dichloroethane was applied onto the carrier generation layer by a dip coating method, and the dry weight was determined.
A carrier transport layer of 19 g/m ² was formed, thereby forming an electrophotographic photoreceptor of the present invention (Sample No. 1). Example 2 When preparing a coating solution for forming a carrier generation layer, after pulverizing a purified pigment, 30 g of polycarbonate resin was mixed with 1.
A carrier generating layer having a dry weight of 2.1 g/m ² was formed in the same manner as in Example 1, except that the dispersion treatment was carried out using a solution dissolved in 1000 ml of 2-dichloroethane. As a result of observation using an electron microscope, the carrier generation layer was filled with pigment particles having an average particle size of 0.3 μm. Furthermore, in the same manner as in Example 1, drying was carried out at 19 g/m ²
An electrophotographic photoreceptor of the present invention (sample No. 2) was prepared by forming a carrier transport layer. Example 3 The anthorone pigment in Example 2 was replaced with a dibenzpyrene quinone pigment "Indanthrene Golden Yellow RK" (CINo.
59105) was used in the same manner as in Example 2,
An electrophotographic photoreceptor of the present invention (sample No. 3) was prepared.
As a result of electron microscopic observation, the carrier generation layer was filled with pigment particles having an average particle size of 0.5 μm. Example 4 The anthorone pigment in Example 2 was replaced with a pyranthrone pigment "Pa" represented by the structural formula C4.
An electrophotographic photoreceptor of the present invention (sample No. 4) was prepared in the same manner as in Example 2, except that "-liogen Red 3340" (manufactured by BASF) was used. As a result of electron microscopic observation, the carrier generation layer was filled with pigment particles having an average particle size of 0.4 μm. Example 5 After pulverizing 30 g of the purified pigment obtained in Example 1 in a ball mill for 24 hours, 100 g of polycarbonate resin was prepared.
and 100 g of hydrazone derivative represented by structural formula P5
A solution prepared by dissolving 1,2-dichloroethane in 1000 ml was added thereto, and a dispersion treatment was further carried out for 24 hours to obtain a coating solution for forming a photosensitive layer. This coating solution was applied by a dip coating method onto the intermediate layer prepared in the same manner as in Example 1 to form a photosensitive layer with a dry weight of 24 g/m ² .
An electrophotographic photoreceptor of the present invention (sample No. 5) was prepared.
As a result of electron microscopy, the photosensitive layer has an average particle size of 0.8 μm.
filled with pigment particles. Example 6 Sample No. 6 was prepared in the same manner as in Example 2, except that the particle size of the purified pigment was changed. The average particle size of the photoconductive particles in each of these samples is shown in the table below. Comparative Example 1 Comparative sample No. 1 was prepared in the same manner as in Example 2, except that the pulverizing operation of the purified pigment was omitted. As a result of electron microscopic observation, the average particle size of the pigment particles in the carrier generation layer was 2.5 μm. Comparative Examples 2 and 3 As a carrier transport substance, 1,1-bis-[4-
Comparative sample No. .2 and No.3 were created. Comparative Example 4 Comparative sample No. 4 was prepared in the same manner as in Example 2, except that the commercially available polycyclic quinone pigment in Example 1 was used as the organic pigment without sublimation purification. Sample No. 1~ obtained in the above Examples and Comparative Examples
No. 6 and comparative samples No. 1 to No. 4 are mounted on a drum testing machine, and the charging potential V ₀ and the exposure amount E 1/2 (lux・sec) required to attenuate V ₀ to 1/2 I asked for
The results are shown in Table-1. Next, each sample was mounted on a modified U-BixV2 (manufactured by Konishiroku Photo Industry Co., Ltd.) and developed using a two-component developer.
A live-action test was conducted on 10,000 copies. At the same time, the black paper potential V _B (v) and white paper potential V _W (v) when black paper and white paper with an optical density of 1.3 are used as manuscripts are measured using an "electrostatic voltmeter model 144D-1D".
(manufactured by Monroe Electronics Inc.). The results are shown in Table 2 along with the occurrence of toner filming.

【table】

【table】

[Table] *Breakdown potential: Breakdown potential is the potential at which white spots begin to appear on the image when the charging potential is changed.
It was set as a lake down potential.
In the above table, the upper row of each image potential is the black paper potential V _B
(v), and the blank paper potential V _W (v) is shown in parentheses at the bottom. Note that the amount of variation indicates an increase, and indicates a decrease. From the above results, based on the present invention, the average particle diameter of polycyclic quinone pigment particles (photoconductive particles) is set to 2.0 μm or less (preferably 1.0 μm or less, more preferably 0.5 μm or less).
m or less), and when a hydrazone derivative is used as a charge transport material, high sensitivity is maintained, it can withstand repeated use, stable image quality, and is resistant to breakdown and toner filming. A photoreceptor can be obtained.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional electrophotographic photoreceptor;
The figure is a schematic enlarged cross-sectional view. 3 to 4 show embodiments of the present invention, and FIG.
FIG. 4 is a schematic enlarged sectional view of various electrophotographic photoreceptors. In addition, in the reference numerals shown in the drawings, 1... substrate, 2... carrier generation layer, 3... carrier transport layer, 4... photosensitive layer, 5... photoconductive particles.

Claims (1)

[Scope of Claims] 1. Average particles consisting of at least one selected from the group consisting of each polycyclic quinone pigment of the following general formula (A), (B) or (C) and obtained by a sublimation purification method. Diameter 2μm
A photoreceptor characterized in that the following photoconductive particles are used as a carrier generating substance, and a hydrazone derivative of the following general formula (P) is used as a carrier transporting substance. (However, in each of the above formulas, X represents a halogen atom, a nitro group, a cyano group, an acyl group, or a carboxyl group, n represents an integer of 0 to 4, and m represents an integer of 0 to 6.) (However, in the above formula, R ¹ represents a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, and R ² represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group) represents a hydrogen atom, a halogen atom, an alkyl group,
It represents a substituted amino group or alkoxy group, and l represents an integer of 0 or 1. ) 2 The photosensitive layer is formed by a laminated structure of a carrier generation layer containing a carrier generation substance as a main component and a carrier transport layer containing a carrier transport substance as a main component.
Photoreceptor described in section. 3. The photoreceptor according to claim 1, wherein the photosensitive layer is formed of a two-phase structure in which a carrier generating substance is dispersed in a carrier transport phase containing a carrier transporting substance as a main component.